*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: #f5f7fa;
    color: #333;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.site-header {
    background: #2c3e50;
    color: white;
    padding: 0 24px;
    height: 60px;
    display: flex;
    align-items: center;
    box-shadow: 0 2px 6px rgba(0,0,0,0.2);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    max-width: 960px;
    margin: 0 auto;
}

.logo {
    font-size: 1.2rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.header-nav a {
    color: rgba(255,255,255,0.85);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.2s;
}

.header-nav a:hover {
    color: #fff;
}

.site-main {
    flex: 1;
    padding: 48px 24px;
}

.container {
    max-width: 680px;
    margin: 0 auto;
}

.upload-section {
    background: #fff;
    border-radius: 12px;
    padding: 40px;
    box-shadow: 0 2px 16px rgba(0,0,0,0.08);
}

.section-title {
    font-size: 1.6rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 8px;
}

.section-subtitle {
    color: #666;
    font-size: 0.95rem;
    margin-bottom: 28px;
}

.alert-box {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 14px 18px;
    border-radius: 8px;
    margin-bottom: 24px;
    font-size: 0.9rem;
    line-height: 1.5;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.alert-icon {
    font-weight: 700;
    font-size: 1rem;
    flex-shrink: 0;
    margin-top: 1px;
}

.drop-zone {
    border: 2px dashed #ccc;
    border-radius: 10px;
    padding: 48px 24px;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
    position: relative;
    background: #fafbfc;
    margin-bottom: 20px;
}

.drop-zone:hover,
.drop-zone.drag-over {
    border-color: #3498db;
    background: #eaf4fd;
}

.drop-zone-icon {
    font-size: 3rem;
    margin-bottom: 12px;
}

.drop-zone-text {
    font-size: 1rem;
    color: #444;
    margin-bottom: 6px;
    font-weight: 500;
}

.drop-zone-hint {
    font-size: 0.82rem;
    color: #999;
}


.file-preview {
    text-align: center;
    margin-bottom: 20px;
}

.file-preview img {
    max-width: 100%;
    max-height: 280px;
    border-radius: 8px;
    border: 1px solid #e0e0e0;
    margin-bottom: 10px;
}

.file-name {
    font-size: 0.88rem;
    color: #555;
}

.upload-btn {
    display: block;
    width: 100%;
    padding: 14px;
    background: #2c3e50;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

.upload-btn:hover {
    background: #3d5166;
}

.upload-btn:active {
    transform: scale(0.98);
}

.site-footer {
    background: #2c3e50;
    color: rgba(255,255,255,0.7);
    padding: 18px 24px;
    font-size: 0.85rem;
}

.footer-inner {
    max-width: 960px;
    margin: 0 auto;
    text-align: center;
}

.site-footer code {
    background: rgba(255,255,255,0.1);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: monospace;
    color: rgba(255,255,255,0.9);
}